A micro-sized microbial solar cell

We report a micro-sized microbial solar cell (MSC) that can produce sustainable energy through photosynthetic reactions of cyanobacteria, Synechocystis PCC 6803 in the anode. The MSC has 57-μL anode/cathode chambers defined by laser-machined poly(methyl methacrylate) (PMMA) substrates. We obtained a maximum power density of 7.09 nW/cm² which is one hundred seventy times more power than previously reported MEMS MSCs. The importance of the light intensity was demonstrated by the higher values of generated current during daytimes than those through the nights, indicating light-dependent photosynthetic processes. Considering that sunlight offers an unlimited source of energy, development of self-sustainable MSCs that rely on light as an energy source will become an increasingly important area of research in the future. In accordance with the MSC, we developed a photosynthetic cathode-based microbial fuel cell (MFC) showing that the use of cyanobacteria can be useful as well as efficient and sustainable catalysts for the cathode since they act as oxygenators.